Precision Actuators Installation and Maintenance
Alignment of the jack (or jacks) directly affects service life. Jacks must be properly aligned in all planes so that the main drive shaft can be turned without evidence of binding. The following steps are suggested but may not always be applicable when installing jacks. It is the responsibility of the end user to determine specific installation procedures.
- The mounting flange of the jack is a precision-machined surface. The worm shaft and lift shaft bearing bores are machined in tight relationship to the mounting flange.
- Start with the load temporarily supported in a position closest to the jack housing(s). Locate the jack by putting the jack in place with the fasteners loosely assembled.
- Level the jacks if necessary. For some applications, a piece of compliant material such as the rubber used for machine isolation bases will help compensate for potential misalignment.
- Check the level of the load, then, actuate the jacks bringing the lift shaft or travel nut nearly in contact with the load. Adjust the position of the jacks so that the jack attachment points are centered on the load mounting points. Tighten the jack mounting screws. If a compliant material is installed, make sure that the fasteners do not compress the material and that there is clearance around the fasteners.
- Rotate the worms to adjust the timing of the lift shafts as necessary to equally distribute the load. Assemble the load mounting hardware and tighten.
- Cycle the jacks from closest to farthest point. For rotating jacks with a lift shaft bearing support, loosen the bearing support fasteners and re-tighten to ensure that the lift shaft is parallel to the guide system.
- Cycle the jacks again and verify that no binding occurs.
Better mounting surfaces will make it easier to align the jack to the load.
The surface(s) to which the jacks are mounted should be flat, smooth and perpendicular to the guides. Note: for rotating worm gear screw jacks, also ensure that the lift shaft is parallel to the guides.
Failure to do this could result in lift shaft stress fracture.
Check the lubrication levels, check the limit switch settings (note: rotary limit switches are not factory set), check the tightness of all fasteners and put the jacks in service.
ActionJac Worm Gear Screw Jacks require minimum maintenance. In addition to maintaining lubrication levels in the gearbox, the following items should be checked: Lifting screws must be kept free of contaminants and should be lubricated. Refer to the lubrication section on pages 206-207 of our Worm Gear Screw Jacks Catalog for appropriate lubrications. If possible, screws should be booted or returned to retracted position when not in use.
For Machine Screw Jacks, lash between the lift shaft and travel nut (or drive sleeve) greater than ¼ the screw pitch indicates the need for replacement of the jack lift shaft drive components.
For Ball Screw Jacks, the ball screw should be checked periodically for spalling of the raceway. In normal operation, ball screw lash does not change significantly over the life of the ball screw.
For all jacks, check the backlash between the worm and worm gear. Lash in excess of 30° for ratios 5:1 to 8:1 and 60° for ratios 20:1 and 32:1 indicates the need to replace the worm and worm gear.Figure 1